Primary hepatic malignant fibrous histiocytoma: clinicopathologic characteristics and prognostic value of ezrin expression.

Primary hepatic malignant fibrous histiocytoma (MFH) is a rare entity with ill-defined clinicopathologic characteristics. We present the largest series to date (7 cases) of primary hepatic MFH, a systematic review of 27 cases published in the English literature, and an analysis of prognostic factors including ezrin expression. The 2 men and 5 women in our series were 34 to 80 years old (average 61 y) and presented with abdominal pain (6/7), systemic symptoms of low-grade fever, malaise, anorexia and weight loss (4/7), and spiking fever (1/7). One case was an incidental finding. Computed tomography and ultrasound revealed a well-demarcated solitary heterogeneous low-density mass ranging from 5.5 to 20 cm (average 12 cm) in largest dimension (5/7), or multiple small nodules up to 2 cm in diameter (1/7) or a 10 cm multiloculated cystic lesion owing to extensive necrosis (1/7). Histologically, a storiform-pleomorphic pattern with variable degrees of necrosis predominated (6/7). A myxoid pattern was seen in only 1 case and this case lacked necrosis. Lymphoplasmacytic infiltration was seen in 3/7 of the cases. Tumors were grade I (1/7), grade II (2/7), grade III (4/7), stage pT1 (4/7), pT2 (1/7), pT4 (1/7), and pT4, cM1 (1/7) at diagnosis. Three patients with tumor cell ezrin immunoreactivity score >or=1 died of tumor within 1 year. Two patients with tumor cell ezrin immunoreactivity score <1 survived >4 years after surgery. Combined analysis of our series and previously reported cases suggest that primary hepatic MFH possess certain characteristic clinicopathologic features that may help in making the diagnosis and in differentiating it from other more common neoplasms in the liver. The prognosis of hepatic MFH depends primarily on tumor size and stage at the time of diagnosis. Ezrin expression in tumor cells can provide additional prognostic information and may be a potential target for new adjuvant therapies.